On a Study of the Use of the (T˙) Integral in Fracture Analysis of Solids With Inelastic Rate-Constitutive Laws

1982 ◽  
Vol 104 (4) ◽  
pp. 331-337 ◽  
Author(s):  
M. Nakagaki ◽  
S. N. Atluri
Keyword(s):  
Plastic Material ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Constitutive Law ◽  
Fracture Criteria ◽  
Elastic Plastic ◽  
Infinitesimal Deformations ◽  
History Of ◽  
Elastic Plastic Material ◽  
Radial Loading

Here, the following topics are discussed: (i) a new integral (ΔT1) of relevance in the presence of cracks in an elastic-plastic material characterized by a rate-independent incremental constitutive law under the assumption of infinitesimal deformations, (ii) the conditions for path-independency of this integral, (iii) the physical meaning of (ΔT1) whether or not it is path-independent, (iv) its relation to J under conditions of radial loading when deformation theory of plasticity may be valid. The features of this new parameter (ΔT1) are brought out in a numerical solution of a compact tension specimen which is subject to a history of (displacement-controlled) loading/unloading/reloading. The implications of the present results in the context of more rational elastic-plastic fracture criteria are briefly discussed.

The Effect of Discontinuous Crack in Creep Crack Growth Tests

2013 ◽  
Author(s):  
Nak Hyun Kim ◽  
Yun Jae Kim ◽  
Catrin M. Davies ◽  
Ali Mehmanparast ◽  
Kamran M. Nikbin
Keyword(s):  
Crack Growth ◽  
Main Crack ◽  
Plastic Material ◽  
Creep Crack Growth ◽  
Crack Tip ◽  
Limit Load ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Elastic Plastic ◽  
Creep Crack

Discontinuous cracks ahead of the leading crack tip may be present in observedcertain creep crack growth tests as well as in components. In this work, a single crack of different dimensions and distance from the leading crack has been numerically modeled in a compact tension specimen using elastic, elastic-plastic and elastic-plastic-creep loading. In order to examine their effects on fracture mechanics parameters a sensitivity analysis was performed to determine the effects of size and distance of the secondary crack with respect to the main crack. t The elastic analysis shows that the compliance is insensitive small cracks ahead of the main crack. Limit load analyses, assuming an elastic-perfectly plastic material, show that the limit load decreases due to the presence of discontinuous cracks ahead of the main crack. Theload versus plastic load-line displacement response of the specimen was significantly influenced by discontinuous cracking. The J contour parameter and C*-integral have been evaluated at the three crack tips and the average of all of them derived for the appropriate contours were compared with the valuesobtained from on ASTM E1820(1) and E1457(2). Whilst the average values of the contour integral are similar to the ASTM J and C* values there is significant differences in J and C* for the individual crack tip values. This need to be further evaluated in future work.

Structural Integrity Research for Reactor Pressure Vessel Under In-Vessel Retention of a Core Melt

2016 ◽  
Author(s):  
Yongjian Gao ◽  
Yinbiao He ◽  
Ming Cao ◽  
Yuebing Li ◽  
Shiyi Bao ◽  
...  
Keyword(s):  
Pressure Vessel ◽  
Material Properties ◽  
Power Plants ◽  
Structural Integrity ◽  
Plastic Material ◽  
Plastic Region ◽  
Reactor Pressure Vessel ◽  
Elastic Plastic ◽  
Elastic Plastic Material ◽  
Reactor Pressure

In-Vessel Retention (IVR) is one of the most important severe accident mitigation strategies of the third generation passive Nuclear Power Plants (NPP). It is intended to demonstrate that in the case of a core melt, the structural integrity of the Reactor Pressure Vessel (RPV) is assured such that there is no leakage of radioactive debris from the RPV. This paper studied the IVR issue using Finite Element Analyses (FEA). Firstly, the tension and creep testing for the SA-508 Gr.3 Cl.1 material in the temperature range of 25°C to 1000°C were performed. Secondly, a FEA model of the RPV lower head was built. Based on the assumption of ideally elastic-plastic material properties derived from the tension testing data, limit analyses were performed under both the thermal and the thermal plus pressure loading conditions where the load bearing capacity was investigated by tracking the propagation of plastic region as a function of pressure increment. Finally, the ideal elastic-plastic material properties incorporating the creep effect are developed from the 100hr isochronous stress-strain curves, limit analyses are carried out as the second step above. The allowable pressures at 0 hr and 100 hr are obtained. This research provides an alternative approach for the structural integrity evaluation for RPV under IVR condition.

On Determining Elastic Modulus from Instrumented Indentation

2013 ◽  
Vol 668 ◽  
pp. 616-620
Author(s):  
Shuai Huang ◽  
Huang Yuan
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Plastic Material ◽  
Instrumented Indentation ◽  
Computational Simulations ◽  
Elastic Plastic ◽  
Modified Method ◽  
Plastic Materials ◽  
Elastic Plastic Material ◽  
Elastic Plastic Materials

Computational simulations of indentations in elastic-plastic materials showed overestimate in determining elastic modulus using the Oliver & Pharr’s method. Deviations significantly increase with decreasing material hardening. Based on extensive finite element computations the correlation between elastic-plastic material property and indentation has been carried out. A modified method was introduced for estimating elastic modulus from dimensional analysis associated with indentation data. Experimental verifications confirm that the new method produces more accurate prediction of elastic modulus than the Oliver & Pharr’s method.

scholarly journals Relationship Between Rockwell C Hardness and Inelastic Material Constants

2002 ◽  
Vol 124 (2) ◽  
pp. 179-184 ◽  
Author(s):  
Akihiko Hirano ◽  
Masao Sakane ◽  
Naomi Hamada
Keyword(s):  
Finite Element ◽  
Friction Coefficient ◽  
Strain Hardening ◽  
Yield Stress ◽  
Plastic Material ◽  
Stress And Strain ◽  
Material Constants ◽  
Elastic Plastic ◽  
Elastic Plastic Material ◽  
Hardening Coefficient

This paper describes the relationship between Rockwell C hardness and elastic-plastic material constants by using finite element analyses. Finite element Rockwell C hardness analyses were carried out to study the effects of friction coefficient and elastic-plastic material constants on the hardness. The friction coefficient and Young’s modulus had no influence on the hardness but the inelastic materials constants, yield stress, and strain hardening coefficient and exponent, had a significant influence on the hardness. A new equation for predicting the hardness was proposed as a function of yield stress and strain hardening coefficient and exponent. The equation evaluated the hardness within a ±5% difference for all the finite element and experimental results. The critical thickness of specimen and critical distance from specimen edge in the hardness testing was also discussed in connection with JIS and ISO standards.

Behaviour Modelling of the Pseudo-Elastic-Plastic Material at Non-Stationary Loading

2021 ◽  
Vol 43 (1) ◽  
pp. 107-128
Author(s):  
P. Steblyanko ◽  
◽  
K. Domichev ◽  
A. Petrov ◽  
◽  
...  
Keyword(s):  
Plastic Material ◽  
Elastic Plastic ◽  
Behaviour Modelling ◽  
Stationary Loading ◽  
Elastic Plastic Material

Fatigue Evaluation in Mixing Zones: Comparison of Different Criteria of Fatigue

2008 ◽  
Author(s):  
J. M. Stephan ◽  
C. Gourdin ◽  
J. Angles ◽  
S. Quilici ◽  
L. Jeanfaivre
Keyword(s):  
Fatigue Damage ◽  
Thermal Stresses ◽  
Plastic Material ◽  
Material Behavior ◽  
Damage Evaluation ◽  
Elastic Plastic ◽  
Different Types ◽  
Elastic Plastic Material ◽  
Fatigue Evaluation

The distribution of unsteady temperatures in the wall of the 6" FATHER mixing tee mock-up is calculated for a loading configuration: The results seem realistic even if they are not still very accurate (see paper PVP2005-71592 [11]). On this basis, thermal stresses are evaluated for elastic and elastic-plastic material behavior. Then, different types of fatigue criteria are used to evaluate the fatigue damage. The paper develops a brief description of the criteria, the corresponding fatigue damage evaluation and attempts to explain the differences.

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